There are many devices which provide additional traction when placed under the wheels of a car stuck on a slippery surface. I am aware of mats, and chains, and steel tracks but nothing as simple as this device or as convenient to use.
This device comprises a bag of flexible material such as cloth having a plurality of lateral fingerlike compartments on one end. When the bag is filled with sand or other fine aggregate, the bag becomes wedge shaped. The material of which the bag is made is preferably flexible enough so that the bag will conform to the tread design of a tire and provide good traction.
To use the device, the end of the bag having the finger, like compartments is placed under the wheel of a car which is stuck on a slippery spot and the car driven onto the bag. As the car moves it rides up on the thick portion of the bag. The thick portion of the bag prevents it from being thrown out from under the wheel, a problem all to often encountered when removing a vehicle from snow or ice.
The bag will conform to any tread pattern and will not damage the roadway or the car in which it is stored.